Extending the shelf-life of live clams, Venerupis corrugata - important aspects of current packaging and advances in modified atmosphere packaging

Venerupis corrugata (pullet carpet shell) is a premium native clam species in Portugal. This species is highly perishable, typically sold live within 3 or 4 days, posing a significant risk of loss. Therefore, efforts to extend its shelf-life are relevant. The impact of the storage temperature (3, 5, 8 and 12 °C) on clams in plastic net bags and the effect of modified atmosphere packaging (MAP) were investigated. The survival percentage and microbiological and chemical parameters were evaluated, as well as sensory characteristics. The survival percentage and sensory aspects results indicate that the longest time with 95% live clams was observed at 5 °C and 8 °C, but lower temperatures (3 and 5 °C) have lower death rates after the threshold. In the MAP tests, the clams were kept closed due to confinement in plastic trays applying a vacuum, before gas flushing that drew the lid film over the clams. However, a negative effect of CO₂ was observed for clams, with lower survival when packaged in 30% CO₂. The shelf-life increased by only 1–2 days under >70% O₂ with no CO₂. These results show that this species is very sensitive, and MAP is not commercially effective for this application.